This 17Cr/4Ni precipitation hardening stainless steel has a combination of high hardness and strength after suitable heat treatment. It also has similar corrosion and heat resistance to Type 304.

A.I.S.I. Analysis

C

Mn

P

S

Si

Cr

Ni

Cu

Mo

.07 max.

1.00 Max.

.040 Max.

.030 Max.

1.0 Max.

15.5 to 17.5

3.0 to 5.0

3.0 to 5.0

0.15 to 0.45

Typical Mechanical Properties – (Annealed)

Yield Strength 2% offset psi

Ultimate Strenght psi

Elongation % in 2″

Hardness

Impact Charpy Ft.-lbs.

Modulus of Elasticity

Rc

BHN

130,000

160,000

15

35

330

30

28.5 x 106

Other Properties (H900)

Creep Strength 1% Flow in 1,000 hrs. at 900°F psi

Coefficient of Thermal Expansion (in/in/°Fx10-6) 32°F-212°F

Electical Resistivity Micohm-Cm at 68°F

Modulus of Conductivity BTU/Ft.2/Hr/°F/Ft.

at 212°F

at 932°F

23

6.0

80

10.6

13.1

Corrosion Resistance

Excellent resistance to the same range of corrosive environments as Type 304 stainless steel.

Heat Resistance

Good oxidation resistance. To preserve mechanical properties and hardness, do not use above 900°F.

Heat Treatment

Solution annealing – Heat to 1900°F for 1/2 hour and cool to 90°F maximum in air. Oil quenching may be used for small non intricate sections.

Hardening

A single low temperature process is employed. Heat to 900°F – 1100°F for 1 to 4 hours and air cool. Typical hardness values after hardening are:

Hardening Temperature (°F)

900

925

1025

1075

1100

1150

Typical Hardness Rockwell C

44

42

38

36

35

33

A decreased in size (shrinkage) takes place during the hardening process, and change must be allowed for in prior manufacturing operations.
The magnitude of the size change is temperature dependent :
900°F – .0005″ approx.
1150°F – .001″ approx.

Can be successfully welded by all standard methods. Preheating is not necessary comparable to those of the parent mental may be achieved in the weld metal by appropriate post weld heat treatment. Somewhat low weld metal ductility may give rise to notch sensitivity. Precaution should be taken in design and welding procedures to avoid concentration of weldmelt stesses.

303

General Characteristics

Type 303 is “18-8” chromium- nickel stainless steel modified by the addition of sulphur, as well as phosphorus, to improve machinability and non-seizing properties. It is the most readily machinable of all the chromium- nickel grades and has good corrosion resistance. It is non- magnetic in the annealed condition and not hardenable by heat treatment.

Typical Analysis: % Maximum unless shown as a range

C

Mn

P

S

Si

Cr

Ni

.15

2.00

.20

.15 Min.

1.00

17.00/19.00

8.00/10.00

Mechanical Properties

In practice, annealed bars will average as follows:

Tensile Strength psi

Yield Strength psi

Elongation on 2″

Rockwell B Hardness

90000

35,000

50%

84

Specifications

The following specifications are generally applicable: MIL-S-7720, AMS-5640, QQ-S-764, ASTM A 582.

Because of the elements which are added to improve machinability. Type 303 has slightly reduced general corrosion resistance.

Machinability

Type 303 has considerably better machining characteristics than the other chromium – nickel grades. It has a machinability rating of approximately 78%, with B 1212 rated 100%. Surface cutting speed on automatic screw machines is approximately 125 feet per minute.

Types 302 and 304 show good resistance to corrosion. They are highly resistant to strong oxidizing acids, such as nitric acid. Intergranular corrosion may occur when material is heated within or cooled through the range of 425°-815°C (800D-1500°F).

Heat Resistance

Good oxidation resistance in intermittent service to 1600° and in continuous service to 1650°F. Continuous use in the 800 – 1575°F range not recommended but often performs well in temperatures fluctuating above and below this range. Type 304L is more resistant to carbide precipitation and can be used in the above temperature range.

Heat Treatment

Annealing – Heat to 1850CF – 2050CF, and cool rapidly. Use the low side of the range for intermediate annealing. This grade cannot be hardened by thermal treatment.

Machinability

Types 302 and 304 have a machinability rating of approximately 45%, with B 1212 rated as 100%. Surface cutting speed on automatic screw machines is approximately 75 feet per minute.

Weldability

Easily welded by all the commercial processes except forge or hammer welding.

310

General Characteristics

With high chromium and nickel content, Type 310 has the heat resisting properties of the more commonly used stainless steels. It has high creep strength and mechanical properties and does not become brittle at elevated temperatures.

Typical Analysis: % Maximum unless shown as a range

C

Mn

P

S

Si

Cr

Ni

.25

2.00

.045

.030

1.5

24.00/26.00

1900/22.00

Mechanical Properties

Tensile Strength psi

Yield Strength psi

Elongation on 2″

Rockwell B Hardness

95,000

45,000

45%

85

Specifications

The following specifications are generally applicable: Sheets : ASTM A 167, ASTM A 240, ASTM A 580

Excellent resistance at normal temperatures and when in high temperature service, exhibits good resistance to oxidation and carburizing atmospheres. Resists fuming nitric acid at room temperature and fused nitrates up to 425°C (800° F).

Heat Resistance

Good oxidation resistance in intermittent service tol 900° and in continuous service to 2100°F. Good resistance to thermal fatigue and cyclic heating. Widely used where sulphur dioxide gas is encountered at elevated temperatures. Continuous use in the 800 – 1575°F range not recommended but often performs well in temperatures fluctuating above and below this range.

Heat Treatment

Annealing – Heat to 1900°F – 2100°F, and cool rapidly for maximum corrosion resistance. This treatment is also recommended to restore ductility after each 1000 hours of service at 1200°F – 1900°F

Weldability

Good characteristics suited to all standard welding methods.

316

Bar

General Characteristics

Type 316 is modified by the addition of molybdenum, which greatly increases its corrosion resistance as well as its mechanical properties at elevated temperatures. Plates are available not only in the regular Type 316 analysis, but also in a low carbon analysis known as Type 316L which precludes any harmful precipitation in the 425°-815°C (800°-1500°F)range.

Highly resistant to the complex sulphur compounds used in pulp and paper processing. Also resists attack by marine and corrosive industrial atmospheres.

Heat Resistance

Good oxidation resistance in intermittent service to 1600° and in continuous service to 1700°F. Continuous use in the 800 – 1575°F range not recommended but often performs well in temperatures fluctuating above and below this range. Type 316L is more resistant to carbide precipitation and can be used in the above temperature range.

Resists dry atmospheres, fresh water, mild alkalies and acids, steam and hot gases. Must be hardened for maximum heat and corrosion resistance. Less corrosion resistant than 300 Series grades and ferritic 400 Series alloys such as Type 430.

Heat Resistance

Good resistance to scaling in intermittent service tol 500° and in continuous service to 1300°F.

Type 410 has a machinability rating of approximately 54%, with B 1212 rated 100%. Surface cutting speed on automatic screw machines is approximately 90 feet per minute.

Weldability

May be welded by all the commercial processes except forge or hammer welding.

416

General Characteristics

Type 416 is made with sulphur to produce a free-machining steel. If is the most readily machinable of all stainless steels. A wide range of mechanical properties may be obtained by conventional heat treating methods.

Typical Analysis: % Maximum unless shown as a range

C

Mn

P

S

Si

Cr

.15

1.25

.060

.033

1.00

12.00/14.00

Mechanical Properties

Tensile Strength psi

Yield Strength psi

Elongation on 2″

Rockwell B Hardness

125,000

110,000

11%

82

Specifications

The following specifications are generally applicable: QQ-S-764, AMS-5610, ASTM A 582